Ultrafast degradation of emerging organic pollutants via activation of peroxymonosulfate over Fe3C/Fe@N-C-x: Singlet oxygen evolution and electron-transfer mechanisms

Fe3C/Fe decorated N-doped magnetic carbon materials (denoted as Fe3C/Fe@N-C-x) were successfully fabricated via facile one-pot calcination of MIL-88B(Fe) with a green precursor of melamine. Benefiting from the coexistence of sp2-hybridized C-pi moieties, oxygen-containing groups (C--O and O-C--O), N-doping species and ferreous nanoparticles (FNPs), the as-obtained Fe3C/Fe@N-C-9 exhibited excellent activation of peroxymonosulfate (PMS) for ultrafast elimination of various emerging organic contaminants with high mineralization capacities. Inspired by the unique nanotube morphology and encapsulation of FNPs, the Fe3C/Fe@N-C-9 possessed trace Fe leaching and can be magnetically separated for an easy recycling. Combining with competitive radical scavenging tests, electron spin resonance (ESR), electrochemical analysis and in-situ Raman spectra, the singlet oxygen (1O2) and electron-transfer can be accounted for the organic pollutant removal. Because of that, the Fe3C/Fe@N-C-9 exhibited good resistance to inorganic anions and natural organic matters (NOMs). It was fascinating that Fe3C/Fe@N-C-9 achieved satisfactory treatment efficiency for real pharmaceutical wastewater.

Automated summary

Fe3C/Fe@N-C-9 materials were successfully fabricated via one-pot calcination using a green precursor. The materials exhibited excellent activation of PMS for fast removal of emerging organic contaminants with high mineralization capacities. The nanotube morphology and encapsulation of FNPs allowed for trace Fe leaching and easy magnetic separation for recycling. Singlet oxygen and electron-transfer were identified as the main mechanisms for organic pollutant removal.